Re: Strengthen pg_waldump's --save-fullpage tests

On Mon, Jan 09, 2023 at 08:30:00AM +0530, Bharath Rupireddy wrote:
> A recent commit [1] added --save-fullpage option to pg_waldump to
> extract full page images (FPI) from WAL records and save them into
> files (one file per FPI) under a specified directory. While it added
> tests to check the LSN from the FPI file name and the FPI file
> contents, it missed to further check the FPI contents like the tuples
> on the page. I'm attaching a patch that basically reads the FPI file
> (saved by pg_waldump) contents and raw page from the table file (using
> pageinspect extension) and compares the tuples from both of them. This
> test ensures that the pg_waldump outputs the correct FPI. This idea is
> also discussed elsewhere [2].
>
> Thoughts?

I am not sure that it is necessary to expand this set of tests to have
dependencies on heap and pageinspect (if we do so, what of index AMs)
and spend more cycles on that, while we already have something in
place to cross-check ReadRecPtr with what's stored in the page header
written on top of the block size.
--
Michael